It depends on how experienced a lifter you are and how strong you are. If you've been training less than a year, the best way to train is with a full body workout performed three times per week. This is still a great way to train for many intermediates or even advanced lifters, depending on how it it structured. However, after you have been training for a while and have built up a decent level of strength, you will probably find you'll improve better if you do an upper/lower split, training three or four days per week. The push/pull/legs and opposing muscle groups split are also good methods for intermediate and advanced people. But for the best combination of strength and size development you can't beat the upper/lower split.